If after the expiry of the credit limit, I will not have accumulated enough funds in the account to cover (refund) the used and non-renewable limit (its part)?

If you do not cover the credit limit on time, late fees (late interest) will be charged for the used and unreturned credit limit (or its part). 

After the expiry of the credit limit, the bank provides the opportunity to fill out the "Card credit limit debt payment application" and apply for debt restructuring into a debt payment (with an agreed payment schedule) agreement. You can find the application in the Citadele Internet Bank ("Lending and Leasing → Applications → Agreement on debt repayment") or by pressing this link: https://mano.citadele.lt/credit-restructuring/. After considering your application, the bank will make a decision, and in case of a positive decision, the bank will make an offer that you can use when concluding a debt payment agreement in Citadele Internet Bank.